WASHINGTON (Reuters) - U.S. Senate Republican leader Mitch McConnell of Kentucky has won re-election to a sixth term, CNN projected on Tuesday, boosting Republican hopes of taking majority control in the chamber.

McConnell, 72, who was first elected in 1984, defeated Kentucky Secretary of State Alison Lundergan Grimes, a 35-year-old Democrat who refused to say during the campaign whether she had voted for the unpopular Democratic President Barack Obama.